Classification automation

A says "X1 = {a1,a2,a3}".
B says "X1 = {a2,a3,a6,a7}".
C says "X1 = {a1,a2,a4}".

then,

If A=B=C
X1={a1,a2,a3,a4,a6,a7} OR
X1={a1,a2} AND

If A>B=C,A>B>C,A>C>B
X1={a1,a2,a3}

If B>A=C,B>A>C,B>C>A
X1={a2,a3,a6,a7}

If C>A=B,C>A>B,C>B>A
X1={a1,a2,a4}

If A=B>C
X1={a1,a2,a3,a6,a7} OR
X1={a2,a3} AND

If B=C>A
X1={a1,a2,a3,a4,a6,a7} OR
X1={a2} AND

If A=C>B
X1={a1,a2,a3,a4} OR
X1={a1,a2} AND

then, someone may resay something to modify previous classification.